Arid exploration terrain in Chile’s Atacama Region.
By Charles Pitts
Capstone Copper has completed its acquisition of the copper assets at the San Pietro copper-gold-iron-cobalt project in Chile’s Atacama Region, adding about 16,000 hectares of prospective ground and an inferred mineral resource to its Mantoverde-Santo Domingo district position.
The consideration for the transaction was US$25 million in Capstone shares, according to the company. Shanghai Metals Market, or SMM, also reported the completion of the deal.
San Pietro is located between Capstone’s Mantoverde, Santo Domingo and Sierra Norte properties. The acquisition consolidates a broader land package in one of Chile’s established copper-producing regions, while giving Capstone additional exploration ground near existing and planned district infrastructure.
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Deal at a glance
| Item | Detail |
|---|---|
| Buyer | Capstone Copper Corp. |
| Asset acquired | Copper assets at the San Pietro project |
| Location | Atacama Region, Chile |
| Land added | Approximately 16,000 hectares |
| Consideration | US$25 million in Capstone shares |
| Main deposits | Rincones and Colla |
| Resource classification | Inferred mineral resource |
| Resource size | 492 million tonnes |
| Copper grade | 0.23% |
| Gold grade | 0.05 grams per tonne |
| Seller | New Golden Exploration Chile SpA |
The acquired assets are held by New Golden Exploration Chile SpA, a joint venture indirectly owned by Golden Arrow Resources and Sociedad de Servicios Andinos. Golden Arrow holds a 75.019% interest in the joint venture, while Sociedad de Servicios Andinos holds 24.981%, according to company disclosures.
Resource adds copper inventory
The San Pietro acquisition includes the Rincones and Colla deposits. Capstone said the deposits host an existing National Instrument 43-101-compliant inferred mineral resource of 492 million tonnes grading 0.23% copper and 0.05 grams per tonne gold.
The resource includes approximately 83 million tonnes of oxide material and 410 million tonnes of sulphide material, based on the company’s disclosure. The tonnages are rounded and represent the principal mineralization types identified in the initial estimate.
Capstone said the resource was reported within a US$4.80-per-pound copper pit shell using a 0.3% cut-off grade. The company also said the estimate was prepared from an independent technical report completed for Golden Arrow, with an effective date of Jan. 24, 2025.
The resource remains classified as inferred. That means the geological confidence is not sufficient to support economic decisions or establish mineral reserves. Further drilling, geological verification, metallurgical work and technical studies will be required before Capstone can assess whether the resource could support a future mining operation.
Copper-bearing exploration core from an exploration-stage project.
Capstone said San Pietro provides a platform for additional resource growth. The company plans to review the existing database and integrate the project into its broader exploration planning for the district.
A larger Atacama footprint
The acquisition strengthens Capstone’s position around Mantoverde and Santo Domingo, two assets that form the core of its Atacama strategy.
Capstone operates the Mantoverde copper-gold mine in the region and owns the fully permitted Santo Domingo copper-iron-gold project, located approximately 35 kilometres northeast of Mantoverde. Sierra Norte, acquired by Capstone in 2024, adds further exploration ground to the regional portfolio.
The company said the San Pietro transaction brings approximately 60,000 hectares under its ownership across the district. Including the exploration option agreement signed with Chile’s Empresa Nacional de Minería, or ENAMI, the broader district position covers approximately 78,000 hectares.
Capstone’s Mantoverde mine is an operating copper asset in the Atacama Region.
The location is important because San Pietro sits near operating and planned infrastructure rather than in an isolated greenfield setting. Capstone said the project is positioned close to Mantoverde, Santo Domingo and Sierra Norte, and may offer opportunities to evaluate shared infrastructure, processing options and district-scale development pathways.
Those potential advantages remain subject to technical and economic evaluation. The San Pietro acquisition does not immediately change Capstone’s production guidance, mine plans or approved capital programs.
Capstone’s Atacama assets process both oxide and sulphide mineralization. The company has described Santo Domingo as a potential source of copper, iron and gold, while Mantoverde produces copper cathodes and concentrates. San Pietro’s combination of oxide and sulphide material could provide additional optionality if future work confirms suitable metallurgy and economic continuity.
Exploration remains the immediate focus
Capstone said several exploration targets have been identified at San Pietro along regional structures associated with mineralization at Mantoverde, Santo Domingo and Sierra Norte.
The company’s immediate task will be to validate the inherited geological information and determine where new drilling could add the most value. That work may include infill drilling within the existing Rincones and Colla resource, testing extensions to known mineralization and investigating targets outside the current resource area.
The project’s polymetallic profile also includes iron and cobalt. However, the disclosed resource figures and the transaction rationale are primarily centered on copper, with gold representing a secondary metal in the current estimate.
As with other exploration-stage acquisitions, the headline resource does not represent mineable reserves or guaranteed future production. The eventual development potential will depend on grade distribution, recovery rates, strip ratio, infrastructure access, permitting, capital requirements, operating costs and commodity prices.
Capstone’s stated objective is to use its regional operating experience and technical expertise to assess those factors within a consolidated district framework.
Seller completes copper-asset sale
For Golden Arrow, the transaction separates the copper-focused concessions from the company’s remaining exploration interests at San Pietro.
Golden Arrow announced that the sale had received disinterested shareholder approval before closing. The company said the consideration was delivered through Capstone shares, with transaction costs, taxes and advisory fees deducted from the value transferred.
The seller retains ground associated with gold-focused exploration targets and has said it intends to use the transaction proceeds and its continuing exposure to Capstone shares to support exploration in Chile and Argentina.
The structure allows Capstone to take control of the copper assets while Golden Arrow and its joint-venture partner retain exposure to the remaining gold exploration package. It also gives Capstone control over the concessions containing the Rincones and Colla deposits.
What comes next
The next phase at San Pietro is expected to focus on technical integration, resource verification and exploration planning.
Capstone will need to establish how the acquired concessions fit with its existing district models and development priorities. It will also need to assess whether the oxide and sulphide resources could complement future processing capacity at Mantoverde or Santo Domingo.
Any such scenario remains preliminary. The company has not announced a mine plan, production schedule or construction decision for San Pietro.
For copper operators and investors, the transaction illustrates the strategic value producers place on contiguous or near-contiguous exploration ground in established mining districts. Capstone is adding a large, underexplored land position for a share-based consideration while consolidating its presence around an operating mine and a permitted development project.
The central question will now shift from ownership to conversion: whether the 492-million-tonne inferred resource and surrounding exploration targets can be advanced into a larger, better-defined and economically viable copper opportunity.
Capstone’s official announcement is available through its news release. For broader market context, see Skillings’ analysis of copper consolidation, supply and valuation risks and its coverage of copper prices, inventories and Chile risk.
